When on the move, storing and transferring video files on and from mobile DVRs is critical. This article looks at different storage and transfer methods as well as special requirements. Integration with other sensor inputs, such as GPS, has expanded the applicability of mobile DVRs to more than just security.
The worldwide mobile video surveillance equipment market is estimated to grow at a compound annual growth rate (CAGR) of 12.6 percent over the next five years to reach nearly US$500 million by 2011, said Alastair Hayfield, Market Research Analyst in the Security and ID Group at IMS Research.
Liability and risk mitigation are the biggest drivers. Users in the transportation industry, especially mass transit agencies in the U.S., are us ing mobile surveillance to investigate liability claims.
¨Transit operators and authorities want to be able to defend themselves against false claims or false accidents because otherwise millions of dollars are spent every year in dealing with these claims,〃 said Mariann McDonagh, Senior Vice President of Corporate Marketing at Verint Systems. ¨If an incident turns into a personal liability claim, the video is available for review.〃
While there is little doubt that mobile video surveillance is becoming a common sight on public transport networks due to the threat of terrorism, it is also deployed to deter and respond to more mundane concerns such as vandalism and attacks on staff and passengers. Vandalism is the most common threat faced by the transportation industry, especially in the public transit sector, McDonagh said. ¨Be it arson, graffiti or seats being removed, the deterrence aspect of having surveillance on board is significant.〃
File Storage and Transfer
File transfer methods include wireless download, flash card, removable hard drive and direct Ethernet connection. Hayfield said the two most popular transfer methods are removable hard drives and flash cards (solid state). ¨Removable hard drives are commonplace in buses and flash cards are popular in police cars and taxis. The vehicle driver or operator periodically removes the hard disk or flash card from onboard DVRs and delivers it to the office.〃
Guy Shahmoon, Product Manager for Mobile DVR Solutions at Verint Systems explained that the typical capacity for a hard disk ranges from 100 gigabytes to 750 gigabytes. The mobile market suffers from vibration and hard disks are not meant to be adopted in such an environment. ¨We added a unique technology to ensure that the hard disk is secure and safe, and that it can run for a long time without affecting disk reliability. We designed a spring, which serves as a buffering device that supports the hard disk to make sure that it does not suffer from vibrations as DVRs do.〃
In the police car market, large volumes of storage are not typically required, Hayfield said. ¨Cameras are not recording continuously but are rather used to capture short video clips of roadside arrests and stops. A standard 20-gigabyte flash card, therefore, is a normal use for such an application.〃
Flash cards are also popular in the taxi camera market since hard-drive storage would be excessive. ¨Cameras in taxis are used to capture only a series of still images when passengers enter the taxi or the driver presses a panic alarm,〃 Hayfield said. ¨Use of flash cards helps keep price of surveillance systems lower, which is an important requirement for taxi operators.〃
Wireless transfer is becoming popular as well. ¨It reduces amount of manpower needed to remove, download and replace an entire fleet of hard-disk drives,〃 said Hayfield. ¨It also means that buses or cars can simply enter a terminal and automatically upload information to a central storage location.〃
McDonagh also sees wireless on the rise. ¨In the U.S., the bus market is starting to look at more wireless applications, because of the growth of wireless networks, especially in major municipal areas, where bus services are thriving. There is more and more building out of mini-wireless networks, and that is helping fuel and drive the trend.〃 In Europe, while wireless download is also becoming more of a standard, it depends on existing infrastructure.
DVRs have Ethernet output so users can connect the Ethernet link to a standard wireless device that accepts Ethernet and video streams. ¨On getting to a depot, the system can download video through the wireless connection,〃 explained Shahmoon. ¨Letˇs say we have an access point at the bus depot and a wireless transmitter on the bus. When the link is established when the bus arrives at the depot, people start downloading video from the DVR to the central location.〃
Trains and Buses
There are specific standards for the heavy-rail systems (any railway infrastructure that does not fall under the category of tram, light-rail or rapid-transit systems). The heavy-rail market requires different input voltages: 12 volts DC, 36 volts DC or 110 volts DC. In the bus or light-rail market, input voltage range is usually 12 volts DC to 48 volts DC.
High voltage can cause electrocution, so wire must be isolated with no ground connection. ¨Through hardware design, the mobile DVR unit has to be isolated from the train ground and electricity,〃 Shahmoon said. ¨If a technician accidentally touches the live chassis and earth at the same time, nothing would happen. This is a mandatory requirement dictated by large train manufacturers in many countries.〃
Other special requirements for heavy-railway systems are fire resistance standards (DIN 5510) and rack-mount capabilities. ¨We have to ensure that the unit can be rack-mounted so that there is nothing supported from the bottom. Installation must also pass all vibration tests.〃
In terms of functions, DVRs for heavy rail and light rail or buses are almost the same. The only differences are derived from standards. For example, in Europe, all video surveillance units for buses must comply with the E-mark standard, which is based on ECE regulations issued by the Economic Commission for Europe.
On a train, cameras are usually installed to cover all door entrances. ¨We work with the installer and user to make sure that they use the right camera in terms of focal lens, day and night, and infrared. This is all based on specific customer requirements,〃 Shahmoon said.
Within the bus and coach video surveillance market, there is a general trend to install more cameras and features per bus, Hayfield said. ¨Where previously a system might have two or three cameras monitoring the doorway and aisle of a bus, going forward, more cameras will be used to give complete coverage the inside and outside a bus.〃
It is more common to see a 40-foot bus carrying eight cameras. Inside the bus, two cameras are mounted near the ceiling at each end of the aisle. The other two cameras watch the two doors and record people getting on or off the bus. Outside the bus, one camera looks straight ahead to capture possible accidents. A camera is placed on each side of the bus; one on the roadside to look for possible accidents and another on the curbside to monitor people getting on and off. Finally, a camera is installed at the rear.
GPS data and sensor inputs, such as turn signals, are recorded with video footage to give a clearer picture of events leading up to incidents. ¨In an emergency management application, if there is something unpleasant happening on the bus, ability to identify exact location of the bus is crucial,〃 McDonagh said.
Liability can be scrutinized. ¨Should a vehicle be involved in an accident, the precise path of that vehicle can be tracked with GPS, establishing liability,〃 Hayfield said. Other sensors also provide operators with a tool to mitigate liability. With GPS, data from accelerometers and shock sensors can assess whether drivers were driving recklessly. ¨If bus drivers are driving excessively fast in an area known to contain speed bumps, video can be used to prove that they are damaging the vehicle.〃
¨With accelerometers, in the event of an accident, severity of impact can be judged to determine whether injuries such as whiplash are justified,〃 Hayfield said. ¨This potentially helps reduce amount of compensation that transport companies must pay in relation to false-injury claims.〃
Integrating GPS and mobile DVRs also enables transport managers to track fuel efficiency and route planning. ¨With GPS, vehicle route can be logged to ensure that the correct route is taken,〃 Hayfield said. ¨As a result, drivers fall under more scrutiny and cannot use buses for personal errands.〃
On-vehicle advertising has also become a reality. ¨By integrating GPS into the vehicle, on-screen displays can be used to advertise shops and stores as they are passed. Transport companies can charge for advertising space and offset the cost of onboard surveillance,〃 Hayfield said.
Dedicated Micros' mobile DVR is exactly such a product. It utilizes monitor outputs so advertisements or route information can be shown to commuters. ¨Messaging can also be fed through monitors using predetermined events to trigger locationspecific information or a range of images preloaded on the mobile DVR unit itself for a controlled stream of advertising," said in the company's prepared statement. "For the customer, the security solution pays for itself.〃